US sprinters Tim Montgomery and Chryste Gaines were given two-year bans on Tuesday for doping offences.

They were found guilty by the Court of Arbitration for Sport after appealing against proposed bans based on evidence gathered in the Balco laboratory case.

The US Anti-Doping Agency had sought to impose four-year bans on the pair.

The ban is from 6 June 2005 and all Montgomery's results and awards since 31 March 2001, including his former world record, will be cancelled.

Despite avoiding a life ban, the 30-year-old will be hit hard by the decision.

Not only will his former record time of 9.78 seconds in September 2002 be stripped away from him, but the American looks set to have his huge earnings from breaking that record confiscated.

Ms White's testimony was both credible and sufficient to establish that the athletes had indeed admitted to have used prohibited substances

CAS statement about Kelli White's testimony

All results and awards claimed by three-time world sprint relay champion Gaines, 35, since 30 November 2003 will also be cancelled.

Neither sprinter tested positive for drugs and both vehemently denied the charges which were issued by the USADA following a criminal investigation into the Balco laboratory in California.

USADA had requested four-year suspensions for both runners, but CAS - the highest court in sport - cut the penalty in half.

CAS said it based its ruling in part of testimony from former world sprint champion Kelli White, who was suspended for two years in 2004 in the Balco case.

White testified that Montgomery and Gaines both admitted to her that they used a prohibited substance provided by Balco.

"The panel unanimously found that Ms White's testimony was both credible and sufficient to establish that the athletes had indeed admitted to have used prohibited substances in violation of applicable anti-doping rules," CAS said in a statement.

When we start getting athletes suspended based on what somebody said, you see what gate that opens up

Tim Montgomery's coach Steve Riddick

The panel said Montgomery and Gaines both declined to testify at their hearings.

USADA can ban athletes without a positive doping test if there is other sufficient "analytical" evidence.

But Montgomery's coach Steve Riddick was critical of the USADA's evidence and White's statement.

"This does not make any sense to me based on what Kelli White said. When we start getting athletes suspended based on what somebody said, you see what gate that opens up," said Riddick.

The coach also revealed that Montgomery may retire from athletics as a result of his ban.

"His exact words were 'This does not make any sense. Please explain it to me'," added Riddick.

"At first, he said, 'I'm done.' But I don't think he is. I think that was just his initial reaction. If he trains like he did last year and the following year he will be ready to run (in 2007)."

IAAF President Lamine Diack called the ruling a landmark CAS decision.

"We also take this opportunity to recognise and thank USADA for its substantial contribution in leading prosecution of these cases before CAS," Diack added.

"It demonstrates once again the need for a complete co-operation between anti-doping organisations if the global fight against doping is to be successful."